AC Programmer Manual Conversion or Vacuum Test Jumper

[Matthew Caprio]

AC Programmer Manual Conversion or Vacuum Test Jumper

Keywords:
AC, programmer, solenoid valve, solenoid switch, vacuum switch, vents, flaps, automatic climate control.

Applies to:
86-88 5000 (and maybe more models and years)

Background:
The solenoid vacuum valves in Audi AC Programmers control the flow of vacuum to the AC vent actuators.  These solenoid valves have a tendency to become clogged or contaminated by oil.  Bypassing these solenoid valves can be useful as a diagnostic tool (to determine if the problem is lack of vacuum, failed signals, or clogged valves), or as a long term solution to convert the programmer to manual operation.

Fix:
A vacuum line jumper can be made from parts inside the programmer to route the vacuum input source directly to the vacuum acutators, bypassing the solenoid valves and all their electronics.  This jumper can be left inside the existing programmer, or can be made with parts from a junked programmer as a stand alone unit.

How to make it:
The jumper consists of 2 parts and some vacuum hose.  The parts are: 1.) the connector block from the AC programmer where the 6 port vacuum connection plugs in.  2.) the vacuum splitter block from the AC programmer where the 1 vacuum input is split into 4 lines that normally feed the 4 solenoid valves.

The ports on the connector block are numbered 1-6.  The ports on the splitter block are numbered 1-6.  Run 4 lines from the connector block ports 1,2,3,4 to the vacuum splitter block ports 3,4,5,6 (the order is not important).  Run 1 line from the connector block port 5 to the splitter block 2.  Cap off splitter block port 1 with the red rubber cap that should already be on there.

Secure all hoses in place with some sort of silicone or glue (nothing that will be sucked in there and clog up anything).

Plug this into the car's clear colored vacuum harness connector with the colorful tubes.  You are ready to run.

This arrangement forces the following conditions:
-recirc door open (no outside air flowing into cabin)
-heater valve closed (no hot coolant flowing into heater core for heat)
-all air routed away from defrost
-all air redirected fully through dash vents at the driver

Notes:
This arrangement is best for summer AC mode.
All other normal programmer arrangements (defrost, bilevel, etc) can be made manually with this jumper by disconnecting (AND CAPPING) the proper line from the splitter block to the connector block.  Both ends must be capped to prevent vacuum leaks and contamination of the vacuum actuators.  Create your own exciting custom settings!  The following table indicates what does what:

Block Port Number - Harness Line Color - Function
1 - red - shuts recirc door AND closes hot flow to heater core (with vacuum applied)
2 - yellow - reroutes air from footwell (default) to half center vents bilevel (with vac)
3 - green - reroutes air from footwell (default) to full center vents (with vacuum applied)
4 - blue - reroutes air from defrost (default) to footwell (with vacuum applied)
5 - black - input vacuum source
6 - no connection - no function

note that port 1 eventually splits to perform 2 functions- closing heater valve and closing recirc door flap.

Other notes:
The splitter block also contains a check valve which prevents air from flowing in the wrong direction.  Test this check valve before you make the jumper to ensure you have a reliable one.  To test, supply a vacuum (or suck with your mouth) on a hose to port 2 on the splitter block.  You should be able to suck, but not blow if the check valve is working properly.

Testing the system with the jumper:
If the jumper is properly made and installed, and your system directs air as indicated above, then you know that 1.) you have adequate vacuum coming from your black hose and the "egg crate" accumulator.  2.) that your actuators are working.  3.) there are no vacuum leaks in your colored vacuum hoses going to your actuators.  Any problems that may exist are either in 1.) AC head (generating the commands), 2.) the connections between the head and the programmer, 3.) the programmer itself or a solenoid valve.

FYI: a commonly reported problem on these cars is that the return spring breaks on the recirc door to leave it in recirc even with the heat on (acting like the vacuum is applied to port 1, but opening the heater valve).  Or, the bracket which supports the return spring cracks.  Another one is that the hose to the recirc door sometimes falls off.  Oh yeah, also there may be a spurious / weak voltage source to the programmer that sometimes is not enough to actuate the solenoids-- this is real difficult one to diagnose, but that's how I learned all of the above in the process.  I'm sure there are more, since this system does NOT age well, but I haven't heard them all.

Good luck, and I hope the list can benefit from this hard learned info.
Matthew Caprio
Austin, TX
88 5ksQ
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